Install MSI with log from shell context menu.
This will create a log file with the name of the MSI package in the directory where that MSI package is located.
Repeated (un)installs of the same MSI package will overwrite previous log files.

Use Veritas WinINSTALL LE for simple modifications to .MSI files; you can find it in the "\VALUEADD\3RDPARTY\MGMT\WINSTLE" directory of any Windows 2000 CD-ROM.